Field of the Invention
The present invention relates to a method for transmitting and receiving data in wireless communication systems, and more particularly, to a method for transmitting and receiving data for a specific service of low latency/high reliability and an apparatus for supporting the same.
Discussion of the Related Art
Mobile communication systems have been developed to provide a voice service while guaranteeing the activity of a user. The areas of the mobile communication systems are extended to a data service in addition to the voice service, and more developed mobile communication systems have been requested since the resources shortage is caused by an explosive increase of traffic and users request services of high speed.
Largely, requirements for the next generation mobile communication system include the acceptance of explosive data traffic, the revolutionary increase of transmission rate per user, the acceptance of the number of connection devices dramatically increased, very low End-to-End Latency and the support of high energy efficiency. In order to fulfill the requirements, various techniques have been researched such as the Dual Connectivity, the massive Multiple Input Multiple Output (MIMO), the In-band Full Duplex, the Non-Orthogonal Multiple Access, the support of Super wideband, the Device Networking, and the like.
Recently, the importance of the 5G mobile communication technology has been increased more and more. And one of the actualized fields is a Reliable Communication.
The Reliable Communication means a new communication service that is realized through the Error Free Transmission or Service Availability for the realization of a Mission Critical Service (MCS).
The necessity of the Reliable Communication has been recognized since it is a part of Machine-Type Communication that satisfies Real-Time requirements for the Traffic Safety, the Traffic Efficiency, the E-Health, the Efficient Industrial Communication, and so on.
In addition, a Reliable Connection should be provided to the Reliable Communication for the applications of delay-sensitive such as the Traffic Safety or the Mission Critical Machine-Type Communications (MTCs) of a special purpose.
Furthermore, the necessity of the Reliable Communication has been also recognized for the purpose of a Medical/Emergency Response, a Remote Control, a Sensing, and the like.
It is anticipated that significant increases are required in the End-to-End Latency, the Ubiquity, the Security, the Availability/Reliability, and the like for the MCSs in comparison with the conventional UMTS/LTE and LTE-A/Wi-Fi.
That is, the commercialized wireless technologies (including 3GPP LTE and LTE-A) proposed up to now fail to guarantee the adequate performance for providing various MCSs in the aspect of the Real-Time requirements and the Reliability requirements.
In addition, as the scenarios that are applicable to the 5G mobile communication environment for the MCSs, the following services may be exemplified.                Control a robot arm remotely in order to realize the Industrial Automation, or transport heavy and large goods through the remote control for Automated Guided Vehicles (AGVs)        Remotely control a drone in order to provide the physical distribution, the remote healthcare service, and other various public services        Safely exchange the information required between vehicles in order to provide an autonomous vehicle service or safely deliver the safety signal that notifies a hidden vehicle that is not detected by a vehicle sensor (e.g., camera, radar, etc.) or a forward collision        
In the case that the radio link (serving link) quality of a serving base station is degraded to an extent of not proper for MCSs although another available alternative base station link is determined, the above-mentioned services should be provided continuously.
Accordingly, in the case that the degradation of the radio link quality of a serving base station is detected and it is determined that the radio link quality of the serving base station is not proper for providing MCSs, a method is required for activating another multilink quickly and for configuring an MCS bearer through the activated multilink.
Owing to the reasons, in order for the Reliable Communication of 5G to be available, a terminal utilizes all radio links around and gives instruction so as to maximize the radio link according to situations, and therefore, the decrease of radio link outage for providing MCS should be considered as an essential element.
However, in the case that the same measurement GAP is configured to the serving base station and alternative base stations and applied to a terminal, as defined in the conventional LTE/LTE-A system, there may occur the problem, which is unable to transmit and receive UL/DL data with the serving base station and the alternative base stations during performing an Inter-Frequency Measurement in the corresponding measurement GAP.
In this case, the requirements of Mission Critical Service that requires the link availability of 99.999% may not be satisfied.